Pulse jet engine with spontaneously ignitable fuel and oxidizer



1953 L. L. DREIBELBIS 2,647,364

PULSE JET ENGINE wrrn SPONTANEOUSLY xcmmausv FUEL AND OXIDIZER.

Filed Sept. 10, 1948 2 Sheets-Sheet 1 I INVENTOR. LOGAN L. DREIBELBIS A TTORNEVS 2 Sheets-Sheet 2 L. L. DREIBELBIS IGNITABLE FUEL AND OXIDIZER Aug. 4, 1953 PULSE JET ENGINE WITH SPONTANEOUSLY Filed Sept. I0, 1948 T l M E INVENTOR- LOGAN L. DREIBELBIS A TTO/Q/VEVS TIME \ v 1 w m E umnmmwmu mmnwwwma Patented Aug. 4, 1953 PULSE JET ENGINE WITH'SPONTANEOUSLY IGNITABLE FUEL AND OXIDIZEB Logan L. Dreibelbis, San Juan, Tex., assignor to The M. W. Kellogg Company, Jersey City, N. J a corporation of Delaware Application September 10, 1948, Serial No. 48,700

3 Claims.

The present invention. relates to jet propulsion and more particularly to a jet motor adapted to operate on an impulsing cycle.

An object of the present invention is to provide a jet motor adapted to substantially fill a predetermined portion of its combustion chamber with fuel and oxidizer before said fuel and oxidizer start to react.

Another object of the present invention is to provide a jet motor of relatively small size capable of generating a large thrust.

Another object of the present invention is to provide a jet motor operating on an impulsing cycle wherein the vibration heretofore inherent in such a motor is greatly reduced.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the apparatus possessing the construction, combination of elements and arrangement of parts which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein:

Fig. 1 is a somewhat diagrammatic sectional plan view taken along the line l-I of Fig. 2, and showing a jet motor constructed in accordance with the present invention; 1

Fig. 2 is a sectional elevation taken along the line II--II of Fig. 1;

Fig. 3 is a curve illustrating the manner in which the pressure in one chamber will fluctuate with time as the cycle repeats; and

Fig. 4 is a curve illustrating the manner in which the pressure in two chambers will fluctuate with time as the two cycles alternate and repeat.

Figs. 1 and 2 disclose a jet motor comprising a pair of combustion chambers it], a pair of injectors l2 and I4 located in each chamber H3 and adapted to inject liquid fuel components into said chambers, a pair of conduits l6 and i8 connected to injectors l2 and M respectively to supply them with said fuel components, and a pair of spring pressed valves 72B carried by injectors l2 and M respectively.

Inasmuch as the two combustion'chambers ID are substantially identical only one will be described in detail. However, corresponding parts in the drawing have been identified by identical numerals, and it will be understood that the description of one chamber applies equally well to both of them.

Each combustion chamber H! is T-shaped and has a generally cylindrical combustion portion 24 forming the top or head of the T,'and a generally cylindrical exhaust portion 2'6 forming the stem of the T. Exhaust portion 26 is joined to the mid-point of combustion portion 24, and the interiors of portions 24 and 26 are in communication with each other. The ends of combustion portion 24 are closed by end plates 28 and 30. Injectors I2 and M are carried by end plates 28 and 30 respectively, and are centrally located thereon so that each of them injects its respective liquid propellant component generally axially of combustion portion 24 in a manner to be subsequently described more fully.

The propellant components preferably employed in the jet motor of the present invention are of the type which ar spontaneously combustible upon coming in contact with each other, as for example, an acid type oxidant, and furfural alcohol. It is desirable, in order to obtain the maximum amount of thrust from a combustion chamber of any given size, to place as larg a charge of propellant as is consistent with the design bursting strength of combustion portion 24 in said portion 24 before combustion starts and generates a pressure in chamber [0 which will close injectors l2 and I4 and prevent any more propellant from entering combustion portion 24 during that particular cycle. Injectors l2 and I4 are so constructed, and so arranged in combustion portion 24, that each of them can introduce a relatively large charge of propellant component, each charge being of correct volume, into said combustion portion 24 before said components react with each other.

Injector l2 comprises a hollow cylindrical nozzle 32 having a valve supporting spider 34 located interiorly thereof. A valve 26), comprising a valve stem 38 slidably journaled in spider 2M, and a tapered valve head 36 carried by said valve stem 38, is mounted in nozzle 32 and adapt ed to open into combustion portion 24. A spring 48 mounted on valve stem 38, engages spider 34, and washer 42 carried by valve stem 38, to normally hold valve head 36 seated against tapered surface 44 to close nozzle 32. Injector I4 is substantially identical to injector l2 except for the degree of taper of its valve head 36 and tapered surface 44.

Injectors l2 and It may be connected to conduits l6 and I8 respectively by any desired means. A conventional bolt and flange connection is disclosed in the drawing. Conduits l6 and l8 are connected to sources of supply of fluid propellant components, as for example, conduit l6 may be attached to a pump, or other means, adapted to supply an acid type oxidant under pressure, and conduit l8 may be attached to a pump, or other means, adapted to supply furfural alcohol under pressure. The resistance of springs All is such that when the pressure in chamber i is low, as when sai-d'chamber'has substantially completed the exhaustportion of one cycle, the pressure of the fuel components will simultaneously open valves 20 and permit said components to enter combustion portion 24 of chamber ill. As soon as the propellant starts to burn the pressure immediately rises in chamber [0 and causes valves 20 to close and remain closed until the pressure in said chamber I0 is again reduced.

The tapered surface 44 of injector l2 and the taper of valve head 36 makes such an angle with the center line of combustionportion- 24 that the 1 liquid propellant component supplied by conduit I6 is injected into saidcombustion portion 24 in the form. of a. relatively widely diverging cone, indicatedbydotted lines 46, that approaches the cylindrical wall ofcombustion portion E l adjacent-.the-oppositeend thereof. The tapered surface 44 of injector l4, .and the taper. of its valve head.3$,-makessuchan angle with the center line ofncombustion portion 2 5 that the liquid propellant-component. supplied by conduit i8 is injected intorsaidcombustionportion 24 in the form of azslightly diverging. cone, indicated by dotted lines 48, that contacts thepropellant component cone injectedbyinjector,|2.adjacent to said injector i2... It -will, .theref.ore,.be seen that a stream or cone .ofmprop'ellantsubstantially the length of combustion portion 2.41s injected into said combustion-portion by. each of .the two injectors before .saidstreams .or cones contact each other andignitiomtakes place..,It is thus possible to introducesubstantially twice. the volume of propellantiinto chamber it that would be possible if bothinjectors injected. identical cones of propellant. This larger volume results in rapid combustion of therpropellant.components and very high-thrust inrproportion' to the size of the jet motor.

- :The-frequencyofthe cycles of each combustion :chamber lllof thejetmotor of the present invention is a functionv of the distance between injectors l2 and-.14,- the sizeand shape of combustionportionllland the. ignition lag of the propellant combinationused. Increasing the size of chamber) .will decrease the frequency, and locating injectors=l2 and is closer together will increase theirequencybut will reduce the thrust .ofeach cycle because of the smaller charge injected. Fig. 3 is a. curve that. illustrates the manner ;-in which the pressure.in one chamber it will .fluctuate .as the cycle repeats itself. Inasmuch as theirequencypis quite high, the rapid building up of aapressure in combustion portion at and the rapid. exhausting of thatpressure through exhaust portion-28,. to. obtain and utilize a thrust from saidpressure, results in an intense vibration. The present invention contemplates the use-of the above described chambers it, placed side by side, as: illustrated in Fig. 2, and rigidly .fastenedin that side by side relationship, as by welding or riveting orany other suitable means.

The two chambers in their side by side relationship fire alternately by reason of the coupling provided by the alternate exhaust gas compression waves from each chamber firing of two combustion chambers results in a 19. The alternate total pressure fluctuation. considerably less than the vibration of a similar motor having only one chamber.

; Since certain changes may be made in the above apparatus'without departing from the scope of the invention herein involved, it is intended that allmatter contained in the above description or shown .in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a jet motor, utilizing a plurality of fiuid propellant components which ignite spontaneously upon contact with each other to obtain a propulsive thrust from the resulting combustion the combination of a T-shaped combustion chamber having'a combustion portion and an exhaust portion midway thereof and normal thereto, an injector in one side of said combustion portion, a normally closed-spring loaded valve with a frusto-conical head associated with said injector and serving as a closure therefore and adapted to open into said combustion portion when the pressure in said injector exceeds the pressure in said. combustion portion, said injector being adapted to inject a fluid propellant component into and substantially across said combustion portion in the shape of a diverging conewhen said valve is open, a-second injector in the opposite side of said combustion portion, said second injector being located across said combustion portion and opposite said first mentioned injector, a normally closed spring loaded valve with a frusto-conical head associated with said second injector and serving as a closure therefore and adapted to open into .said combustion portion at substantially the same time that said first mentioned valve opens, said frusto-conical heads having. dilferent halfangles, said second mentioned injector bein adapted to inject a second fluid propellant component substantially across said combustion portion and inside of said diverging cone when said valves are open, whereby said second propellant, component first contacts said first mentioned propellant, component adjacent said first mentioned injector.

. 2. In a jet propulsion device adapted to employ a liquidpropellant made up of a plurality of components which ignite spontaneously upon contact with each other, the combination of a combustion chamber including a closed ended, elongated combustion section and an. exhaust section opening into said combustion section intermediate the ends thereof, said exhaust section having an outlet opening of fixed cross section throughout the to supply said components to said combustion sect1on for spontaneous ignition therein, and

valve means in the combustion section ends of saidconduit means biased. to shut off flow out of said ends-when the pressure in said combustion section approaches thepressure in said conduit means; said valve means including shaped surfaces diflerentially inclined relative to the longi- 75.-

tudinal. axis. of saidcombustion section forming amass;

the components supplied into said combustion section into diverging cones of different slopes intersecting adjacent one end of said combustion section. j

3. In a jet propulsion device adapted to employ a liquid propellant made up of a plurality ofcomponents which ignite spontaneously upon contact with each other, the combination of a T-shaped chamber having a combustion section and an exhaust section midway thereof and normal thereto, said exhaust section provided with an outlet opening of fixed cross section throughout the operation cycle of the propulsion device, means at each end of said combustion section for intermittently admitting the components of the liquid propellant into said combustion section, each of said component admitting means including a substantially unrestricted conduit opening into said combustion section and a valve controlling the flow out of said conduit, said valve biased to close said conduit when the pressure in said combustion chamber approaches the pressure in said cong duit, said component admitting means being in opposed relation whereby said components impinge each other as they are admitted into said combustion chamber.

LOGAN L. DREIBELBIS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,036,288 Matricardi Aug. 20, 1912 1,415,780 Bowen May 9, 1922 2,480,626 Bodine, Jr Aug. 30, 1949 2,489,051 Sayward et al Nov. 22, 1949 FOREIGN PATENTS Number Country Date 27,724 Great Britain Dec. 16, 1907 2,209 Great Britain Jan. 31, 1908 176,838 Great Britain Mar. 6, 1922 522,935 Great Britain July 1, 1940- 630,180 Germany Sept. 24, 1936 

